Remove the executable bit from scanner.cc file.

Patch from Thiago Farina <tfarina@chromium.org>.

TBR=yangguo@chromium.org

Review URL: https://codereview.chromium.org/14081021

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14385 ce2b1a6d-e550-0410-aec6-3dcde31c8c00